User:Tilman Schirmer/Sandbox 201

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PleD

Overview


PleD from Caulobacter crescentus is a response regulator with an unorthodox catalytic, diguanylate cyclase, output domain. It is composed of a canonical CheY-like response regulator receiver (Rec ) domain, a Rec-like (Rec' ) adaptor domain, and a C-terminal GGDEF domain that confers the catalytic acitvity.



The GGDEF domain is named after the highly conserved signature motif (in PleD it is GGEEF) that locates to a β-hairpin.

Substrate binding


The motif is part of the substrate binding site as identified in the structure of PleD in complex with  GTP-alpha-S / Mg++. The GGDEFY domain binds only one GTP subsrate molecule. For the reaction to proceed, two GTP loaded GGDEF domains have to align antiparallely. MODEL.

Allosteric product binding site


C-di-GMP
C-di-GMP monomer

C-di-GMP 'dimer'

Primary inhibition site (Ip)
Primary inhibition site

Secondary inhibition site (Is)
Secondary inhibition site

Primary and secondary inhibition sites
Primary and secondary inhibition sites

Primary and secondary inhibition sites + 5GP

Two conformations


<applet load='1w25' scene='User:Tilman_Schirmer/Sandbox_201/Loose_dimer/3' size='250' frame='true' align='left' caption='non-activated (1w25)' /> <applet load='2v0n' scene='User:Tilman_Schirmer/Sandbox_201/Tight_dimer/2' size='250' frame='true' align='center' caption='activated (BeF3- modified; 2v0n)' />